Telephone-exchange system.



E. E. CLEMENT TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED NOV. 11, 1905. 1,107, 1 39.

Patented Aug. 11, 1914-.

Witmzoaw E. E. CLEMENT. TELEPHONE EXCHANGE SYSTEM.

APPLIOATION FILED NOV. 11, 1905. 1,1011 39, I Patented Aug. 11, 1914.

4 SHEETS-$11331 2.

Witness '12:. E. CLEME T. TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED Nov". 11'; a05- 1,107,1 39, BaLente'd Aug. 11, 1914.

'iSHEBTS-SHFBT 3.

uoeutoz E. E. CLEMENT.

- .TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED NOV.-11, 1905. 1,107,139 Patented Aug. 11, 191i 4 SHEETS-SHEET 4.

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NiliFED STATE-S PATENT OFFIQE.

EDWARD E. CLEMENT, OF WASHINGTON, DISTRICT OF CGLUMBIA, ASSIGNOR, BY MESNE ASSIGNMENTS, .TQEREDEBICK C. STEVENS, OF 'ATTIOA, NEW YORK;

TELEBHONE EXCHANGE SYE'IEM.

monies.

Specification of Letters Patent.

i npplicati on filed November 11, 1905. Serial No. 285,887.

. Patented fang. 1914:.

\Vashington, in theDistrictof Colombian.

have invented certainnew and. useful Im provements in Telephone-Exchange .Systems, of which the'following 1s aspeclfication, reference being had therein.to;the ac} companying drawing.

My.- invention relates to telephone lex} change systems,- and has .for its object the improvement of such systemsin the manner to be hereinafter set forth. 1

In attaining mymbject I provide a common batteryexchange system having two:

wire metallic subscribers." lines, with means at eachsubscribers station both totalk and to signal by making and breaking the cir-' ,cuit, and means at the central office. 0 ntrolled by the subscriber to dothree. things,

-,vi z., first, whenthe subscriber takes. down his receiver his line is connected automatically to an idle connection terminah; sec- 0nd, the thousands and hundreds digits of cord arrangement. 1

the. number wanted are. received-and indicated-upon asuitable mechanism associated with said connection terminal; third, the said connection. terminal having been connected-by an "operator to a'trunk corresponding tothe number shown by the indicator,

the subscriber is'thus given control of.a connector switch. containing the terminals of 100 lines, and the last two digits of the number. he sends work this connector switch to select-the particular line he .Will'ltS.

According to one enibodin entmfony ,invention the line-terminals at central may be plugs, and according to another they may be jacks.

The present invention contemplates plug terminals, or what is known. as a single Referring to the accompanying drawings,

in which my invention is illustrated, Figure l is a diagram of the subscribers station and line, the central ofiice terminal apparatus therefor, and a connection terminal. Fig. 2 is a diagram of a trunk line and an automatic connector switch. Fig. 3 is a iront elevation of the form of connector switch ,shown in diagram in F1g. 2. Flgxl is a bottom plan View of the switch banks-and a wiper arm. Fig. 5 is a front view par retarded relay which may be employed.

Y in section'of a form of having the usual transmitter T, receiver R,

ringer Q, condenser C and a sending key K.

Each station: also has aspecial signal I'BCQlVr ing device. Q, polarizedso that it, responds only to current of one; direction. From the sub-stationlthe line-wires 1- 2, pass to the central office, where., they. terminate in con- ,tacts wand 12. ofjtheacut oif relay N, these contacts. being normally closed..upon. back contacts connected by. wires 3. and t to the magnet M and. the. ground,-respectively.

The magnet, whichv is a part of the line re- 1ay, M, is connectedbn the other, side through wire 5 .to the lnain'battery B, and

its armature,.m, which is connected to. the

same Wire 5, controls the circuit Gwhich ter- Inmates in the-contact m inthebanks of the switch M, which I shall designate the pri 'mary Selector. Thisswitch is'shown ashaw ing itsmoving parts constantly. rotated, .s0. as to-sweep a pair of contacts, at, m?,-a round and around over a circle of fixed contacts'm and I m There are a numberi of primary give each line multiples in tenswitches, so,

that when that line calls and makes its-conby.any one of the, ten .switches,-. this would mean thatvthe total number of primary selectors would be equal to ten per .c entnof all .the lines coming into. the exchange :This

proportion may increase I or. decrease without .186 selectors in. an exchange, varying according. to the number of lines. If, as llhavezfound tarts 777/ test busy it may be fpickedup affecting the merits of the invention. The

'switch comprises a spindle m, ahub m; a

tubular, arm m, containing an operating plug m and carrying the springs-inflow together with the. banks or rings of contacts m, 972 ,421 m", m, m, there being one of each of these contacts for eachline in each primary selector switch bank. The contacts.

m m*'are common, that is connected together. forming the terminals of the trunkwires 7 and Spassing to the connection ter- Ininal shown in thiscase asa plug P. The

contacts m, m. are line-terminals, connected by the wires 9 and 10 was front contacts of the cut-off relay N. Contact m is a test contact, controlled by the line-relay, as already stated, and. contact wa is the terminal ofthe special. holding wire 11 through which ate the switch is controlled by the relay S, as-

- will be pointed out presently. The springs in) to m are mounted with interposed insulation m, in a manner well understood by those skilled in the art, so they are rigidly held in a circle around a spindle m The contacts mm and m rn are provided with platinum contact points, so that when the plug m is inserted into any group to 10 complete the talking circuit, good contacts are assured.

The spindle m is supposed to be driven by means of the belt 122, passing over he wheel m It may, however, be otherwise 15 driven and controlled by the line relay m.

The plug m is connected to a soft iron core m sliding in the tube m and controlled by the magnet windings m and m. Both of these windings are grounded on one 20 side, and on the other side m" is connected "to the spring contact 1227, while m is 0on nected to the spring m. When retracted, which it normally is, the core m takes into ,the notch formed in the spindle m thereby locking the arm m" and all its connected parts, as well as the sleeve m", to the spindle, to be. rotated thereby. The passage of current in either winding of the magnet, however, draws in the core m projects the 30.plug m forward through one of the back openings in the ring m and simultaneously unlocks the arm and spring from the spindle.

' The arm then stops, and remains stationary as long as current is passing through the magnet winding.

The wires 7 and 8 pass to the condensers C, from which the wires 13, 1 are taken on the other side to the tip and ring, respectively, of the plug P. The sleeve of this 40 plug is connected through cord-conductor 15 to a cut-oti' relay N, and thence to the battery wire 12. The idea is that when the plug 1 is inserted in a line or trunk-jack the cut-01f relay removes all signal apparatus from connection with the cord.

The circuit 713, 8-44 is the same in most respects as the cord-circuit ordinarily used in common battery exchanges, that is {it has on the answering end, which termi- 5o nates in the primary sel ctor M, a pair of bridged relays S, S, which jointly control the supervisory clearing-out lamp 8". Then relay S is on the battery through the wires 16, 17, and to line through the wires 18 and" 8, taking current through these wires and through the cut-off relay as soon as connection is made with a line. The relay S, on the other hand, is controlled by the subscriber, either through his switch-hook H,

or through the key K. When the magnet S "is energized it connects the battery wire 17 with! the wire 19 leadi g to the armature of inlay S, and also puts attery on the wire 20, normally connected through the branches 21 and 22 with the wires 14 and 13 The purpose of this is that when the plug P is put in a trunk-jack leading to an automatic switch, the switch will first get current over both sides of the trunk, so that it will surely be restored to its zero position, before starting to pick out the line wanted. There is no communication by word of mouth in this system between the subscriber and the operator. The subscriber sets up an indicator before the operator, which gives the first half of the number of the subscriber wanted. This indicator mechanism, is controlled, as well as the automatic switching mechanism by the relays S S, S and S, and the indicators are finally cut off from the cord by the relay N.

The relays S S? are so constructed as to require a considerable time for their armatures or their cores to retract after being attracted. These relays are preferably solenoids, which pull up their cores quickly, but are fitted with check valves to form dashpots so that the cores will sink down very slowly. Solenoid Siis connected on one side to the back contact of the armature of the relay S; solenoid S is similarly connected to the front contact of the armature'of relay S, and both solenoids are grounded on the-other side. Both have their cores normally retracted. When S is energized it pulls up and momentarily closes together the springs e and s, but this produces no effect, since their circuit 23 is normally open at the armature of relay S. Once up this core does not fall back again until there is a prolonged break, which is when'the subscriber A hangs up at the end of the conversation. The solenoid S on the other hand, closes together all the springs s, s, s when it is down, and simultaneously opens the springs 8 8*.

s and s are the battery springs, and by this means, as will appeailater, momentary impulses are sent over the wire 13, or restoring impulses are sent over both wires 13 and 14, according to the condition of relays S and S During the transmission of a signal both the solenoids S S remain effectively energized, as will appear from the statement of operation, the core of solenoid S dropping upon aprolonged make in the lii1e, and the core of solenoid S dropping on a prolonged break in'the line only.

The function of the relays S and S is to connect and disconnect the indicator magnets I, I to the relay circuit 24 in proper, The normal position of all the sequence. parts is shown in Fig. 1, the armatures of both relays being retracted, and the wire 24 being continued through the armature s and the wire 25 to the indicator magnet I, the other side of which is connected through wire .26 and the armature n of N to ground. When the relay S is energized. which it is over the circuit 23 andthe back contact of its own armature 8 upon the retraction of the core of the solenoid S the two armatures a and a are attracted, the latter connects the winding of the relay 8* 5 directly to the battery wire 12, the relay being thus self locking, and the other armature connects the energizing wire 24 to the wire 27 leading. to the indicator magnet If, which is also. grounded on its other side it through the wire :28, and the armature of the relay N. A third armature 8 of the relay S or rather a third pair of contacts con trolled by said relay, ground the winding of the relay S when the first relay is energized and locked] The second relay is thus prepared to act, but does not so act.

In order to remove the possibility of marginal wear in these relays, aguard relay anay be employed brought in at the same time as the relay S and acting to open the cilcuit of the latter until the core of S has made another excursion up and down. Or, instead of the relays S and S I may use a side switch of the type shown in Fig. 3, op

crated by one magnet as 8, controlled by the solenoid S and restored by another magnet as N.

Fig. 2 shows the circuit of a trunk and of an automatic connector switch. It also shows a sabscribers station A, which, in the present case, is supposed to be the station called. Before proceeding to describe these circuits I will first describe the mechanical features of a type of switch which may be used. It

will be understood that I present the mechanisms shown in Figs. 3 and 4 as typical, and not as a finished embodiment of improvements. In order to render this specification clear and easily intelligible, I have taken a 40 switch of what is known as the Strowger or automatic electric pattern, and'havo hii ranged the actual working parts thereof in a frame, all in one plane, or nearly so, so that all of the parts can be seen, and their workings understood, at a glance. This I frame is indicated at F, and forms a hollow rectangle, preferably with a back plate f, ,upon which the parts can be mounted. In this frame is journaled a vertical spindle f provided at its lower end with contact wipers f and f and near its upper end with rotary and vertical ratchets f and f. The former of these is engaged by a pawl f, of the rotary magnet V, and the latter is engaged Ey'the pawl f of thevertical magnet V. Both. the ratchets are engaged by a bifurcated, detent f pivoted between posts on the plate This detcnt normally holds the spindle in any position to which it is set, being maintained in engagement with the ratchets by a suitable spring, not

"shown. It is'controlled by the release mag-- net V whose armature carries-at its upper extremity a link 0 which is adapted to be tie/thrust forward when the magnet is enerof one hundred jacks, connectedtp trunks gized, to engage a pin f on. the uprising bell-crank arm of the detent f", so that when the magnet V is denergized the retracting spring of the armature will pull back the detent, lifting its pawls from engagement with the ratchets and f, permitting a coiled spring housed within the cap f to turn the spindle back until its stop arm f strikes the stop f on the post f when the weight of the spindle will pull it down to its normal position shown in the drawing. As long as the. wipers are resting on any row of contacts the spindle cannot drop, hence it must be-turned hack to zero in restoring.

The magnet V, which will hereinafter be called the verticalmagnet, steps up the spindie in response to the first set of impulses, to bring the wipers f f* opposite any deslred row of contacts; a single rotary impulse then comes from theoppo'site side of the line and works the so-called private magnet V which pulls up its armature, and through theescapement '2) permits the side switch lever W to move one step. This switches in the rotary magnet V, which then responds to closures of the controlling relay, shown in Fig. 2, to turn the spindle until the wipers P reach the desired contacts in their respective rows. When the second impulse comes fromrotary side of line, the magnet V steps the lever W another step, and the switch arms w, etc., then cut oif the rotary magnet V, and out on a. ringing relay which is not shown in the mechanical figures. \Vhen the spindle finally returns to its normal resting position the ratchet f? in its downward'travel strikes the short horizontal arm of a bell-crank lever f, the long vertical arm of which presses back the lever W to reset it. I

Atthe expiration of a onnection, when impulses come from both sides of-the line, the circuit of the release magnet V is closed," and it releases the switch spindle,.as already described. The relays which control and 0perate this switch are of ordinary'type, and need no special description, but it is thought: that the switch mechanism and its operation will be sufficiently understood irom-thafore- 115 going, and I will therefore now pro'eeedto jftl'flce the circuits in Fig. 2.

The jack J receives the plug P,"bing' one 29*.30, each of which leads to} connector switch whose banks contain the multiple? contacts of a particularonefhundredlines. Assuming, for instance, that a subsoribers number is 2249i His contact for calling purposes would be No. 9 in the fourth row of the bank of the connector switch numbered 2200. The jack J of said switch would be numbered 22, and the first two digits which" subscriber A would send to set up the indicaters I I in Fig. would'be, therefore, 22. 180

Each trunk 29-30 is supposed to be multipled' to a plurality of onerators positions, and in order to provide for a considerable load onihe same connector group of lines, I preferably provide 3, 5, 7 or more connector switches, trunks, and jacks J for the same one hundred lines. These being multipled to the difl'erent positions on the manual switchboard, of course, a test is necessary to ascertain if any particular trunk line is busy. This test is taken care of in the ordinary way, hence the potential of the outer ring or test thimble of the jack J is raised when the plug is inserted, and so an ordinary test connection of the operators telephone can be made, and she will simply run her plug along a row of acks bearing the same numberuntil she comes to an idle one of the group selected. The trunk contains a number of condensers, c c, which, however, I may short-circuit during conversation. It is convenient to leave these condensers where they are in the present illustration,

hence I shall not describe any means for cutting them .out. They serve to separate the operating end of the trunk, with the vertical and rotary reiay's V"=-V from the calling end, and the bridging magnets X-JQ'.

In order to control the various magnets of the switch, I rovide the vertical and rotary relays V in ground taps from the respective trunk wires 29 and 30. WVhen the relay Vis energized it strikes a local cirfrom ground as follows: 31-3233 34e-35-- to the side switch arm w, then by a wire 36 to vertical magnet V, and to battery B by the key wire 37. After the side switch has moved a step the circuit is continued from the arm a; through wire 38 to the rotary magnet V, and then'by the key wire 37 to the battery. When the side switch has moved another step the circuit from arm to is continued by wire 39 to the rin'gin relay Y, and thence by the key wire 37 to attery. The uertical relay V thus controls all of the active magnets of the switch. The. rotary relay V controls the side switch and what' is commonly called the private magnet V Its local circuit is from ground 31-82%0-41 and 42 to battery. Each time the private magnet V is energized it opens the circuit 34735, closes the test circuit 4344, and moves the side switch arms, which are all fastened together, a single step.

The release magnet V is controlled by both the vertical and rotary relays V.V acting together. \Vhen the impulses come from both sides of line simultaneously, and from the trunk wires 293( to these two relays, the release circuit is closed as follows: 3l4546-4:7-V'"-48, and battery.

With the side switch in its second position,;

will complete a circuit from net V, which steps the wipers around to the desired. number, the next following impulse will energize magnet V then magnet V, and this by closing the test circuit 4344 the wiper f,

to the arm M and by wires 4344 to the release magnet V 'and wire 48 to battery.

If the line wanted is in use there will be a ground on the tip side through either the magnet X of a connector, as shown in Fig.

2, or through the relays S, as shown in Fig. 1. In either case the test will result in the magnet V releasing the switch and preventin connection with the busy line.

%Jn the third step of the side switch'thc trunk wires 49 and 50 are connected through the arms w w to the wipers f", which before that have been cut off, and the last step in the operation is ringing. It will be observed that the closed pairs of contacts y-y is included in each of the conductors 4:9 and 50. A pair of generator contacts, gfig", lie contiguous to these, and are connected to the ringing-generator Gr. After the desired number has been selected, and

the-side switch has moved its final step, the next break produced at the subscribers station by the key K energizes relay V, which closes the circuit of the ringing relay Y. whereby the contacts y-y are separated and the generator G is connedted to the wanted line. I have shown the line to station A provided with a terminal jack J and multiple terminals J These are shown in Fig. 2 in the banks of the switch. The wiper f with the test which I have here described, is of no importance, and may be omitted, hence the test depends upon the presence or absence of a ground on the upper wiper f. The wiper f is shown, however, as the banks upon which it works are sometimes used for other purposes.

The operation. of my system thus described is as follows: Assuming that subscriber A desires connection with subscriber A, he removes his receiver R from the hook, and by. so doing closes his line circuit so as to permit a flow of current from the main battery B through the relay M, which closes the local circuit 6 and puts battery on the line and multiples m in the primary selector switches M. The first one of these switches whose arm m touches the calling line terminal closes a circuit from said terminal through the arm m to the coil m and ground. I may here state that I prefer to ground bigth coils on the frame of the switch. Upon the application of this circuit the core m is violently sucked into the solenoid, withdrawing its ends from engagement with the notch in the spindle in. At the same time the plug m is projected forward into the opening corresponding to the line calling, in the ring m and between the springs m m,-spreading the latter apartand connecting them with the fixed contacts 9n-m ldy this means the trunk conductors i' i are connected to the line extensions 9 -40, and the switch arm stops. Current immediately flows from the main battery ll through the cut-off relay N, by the following path: B, 16, 17, S, 18, 8, m, m", l\ ground. The cut-elf relay N is thereby energized and pulls in the contacts H, in cutting ed the line relay M, and the ground 4, and connecting the line wires 1-2 onto the extensions 9 10. Current then flows out over line wire 2 to the subscribers station, and from line wire 1, through the conductors l5 9 and 7, to the relay S, and ground, so that relay S pulls, up instantly. This puts battery onto the contact m in the switch by the following path: Bl617armature S,- l9-armature of S,11,m As the arm m is resting on the contact m the current continues through this arm to the coil m" and ground, so that as the other coil m has been cut'ofl by the denergization of the line relay M, the coil m" will now continue to maintain the core m and the plug m in their operative ositions, being controlled,

it will be observe by the relay S, which is responsive to the subscribers actions. It should be observed, however, that this re 3,0 lay makes and breaks its local circuits during the process of selection of the line wantcd, but the breaks are of too short duration to affect the selector solenoid, which is very.

slow in its movements.

The line is now connected to the trunk 78, and the subscriber is notified to that affect by the rising of the signal target 9, glue to the reversal of current in his line; for it will be noted that when the plug m {0 is stuck into the line jack the normal conne ions of battery on the line are reversed. Perceiving that he is connected, the subscriber manipulates the key K, sending two groups of breaks, corresponding in number no makes andbreaks will also remain effectively. energized, until a long make, which comes after the first grou of breaks. This first group oil breaks, as

spending impulses of current in the wire 2a,

4a to the first two digits of the number wanted.-

fic re 2i, and this solenoid will pull ,up, quickly, and thereafter during the successive have stated,moves the armature oi? relay S, andproduces'corref which is connected to the armature a, and thence by wire '25 to indicator magnet I, and Wire 26 to ground. The indicator magnet I thereupon steps around its indicator dial or drum as many steps as there are impulses. Assuming the number to be called is .2249, this would-be two steps in the present case.

Having sent this many breaks, the subscriber the wire 23 and through the relay b} by the Relay S thereupon pulls up, looking itself by connecting the battery wire 12 to the armature 8 at the same time disconnecting the latter from the battery wire The armature s shifts the actuating circuit 24, which is controlled by armature s of relay'S, from the indicator wire 25 to the indicator wire 27. The next set of breaks which will also be two in number will therefore produce impulses in the indicator magnet I, and

these will likewise step around its drum or dial and the number 2. Upon cessation of these impulses the solenoid S will again release its core, momentarily close the springs 8'8 and again send a pulse of current over the wire 23, this time through the armature s and the relay 5 to'ground by the armature 8", which was formerly opened. The relay 5 now pulls up, locking itself by connectin-gthe armature a with the battery wire 12, at the same time disconnecting it from the-wire 23. It also connects the armature .9 to the branch 23 of the battery wire 23, for the purpose of putting battery through the wire 16 onto the wires 230 and 11. if this were not done, battery would. be momentarily taken off of the coil m", and the control of the primary selector M would be loshofor when the relay S is thus energized it breaks the connection between 16 and 17. so that thesubscriber will hear a click, and his signal 9 if biased by a spring or weight will bc drawn down out of sight. This means that he must wait a moment before transmitting further. The operator perceiving the nunrl'ier Q2 on the indicators i-li takes. up the plug P and inserts it in the jack 5 (see llig. 2 'of the 22nd group, testinguntil she finds an idle jack of that group. As soon as this plug is inserted in the jack the circuit completed from. the battery wit-e12 through the cut-oil relay 'N. by wire 15 to the sleeve of the plug, and .the outer ring of the jack and ground; The relay hi thereupon pulls up,'and takes the ground oft of magnets I+I, and S, the latter in its retraction taking the ground oif of the relay S,-

The instant the relay S is deenergized,

battery is put back on the wires 1617, the relay S pulls up once more, and the control of the primary selector is restored, also current flows out once more over the line. The signal then rises, and the siibscriber proceeds' to send the last two digits of the number wanted, which are 4 and 9. The first group of breaks, four in number, works the relay S, which sends impulses over the wire 2% through the springs s and s, to the cord conductor 13, the ti of the plug P and the spring of the jack to the trunk conductor 29, vertical relay V and ground. The ver-. tieal relay thereupon makes and breaks the local circuits 3132-333435-3637, and steps up the switch wipers f*, to the fourth row in the bank J As the subscriber then pauses, the solenoid S lets down'its core, and a single inpulse is sent over the rotary side of line from the wire a 230 to 23, s s'-2314 ring of plug,

second contact of jack, wire 30. rotary relay V", and ground. The relay V thereupon closes the following local circuit: 3l32- 4c04-142-4SB. The private magnet V then pulls up, opens 34 and 35, and moves the sideswitch one step, cutting off the vertical magnet V, and cutting magnet V.

The final set of 9 breaks cause 9 impulses over the cord conductor 13 and the trunk wire-29 to the relay V, as before. Nine impulses therefore reach the-rotary magnet V, which turns the spindle 7 until the Wipers. f rest on the 9th contacts in the fourth row. Next, as the subscriber pauses, comes again a single impulse over the rotary side of line 14:30 to rela -V. The private magnet V completes tie test circuit 4344, and at the same time it prepares to step the side'switch its final step. I should here observe that by reason of the escapement it requires an attraction and a retraction both of thearmature of the re lay V to move the side switch one step. Thus, if. the line wanted is busy, the final step will never be taken, for on the attraction of the armature of V, and the prefer to have the indicators.

on the rotary the release-magnet V and the switch will thereupon be returned to its normal position of disuse. Assuming that the line wanted is idle, however, no such effect is produced, the private magnet V retracts its armature, the circuit ti t-35 is again closed as the test circuit is opened, and the side switch arms pass their final contacts. This means that arm w goes on to a blank point; arms 'w''w complete the trunk circuit to the wipers f and arm w connects the wire 35 and the ringing relay wire 39. Finally, in

order to ring the subscriber wanted, the

calling subscriber A resscs the key K-an arbitrary number of times, taking care not to keep the current open a sufficient length of time to retract the core of the solenoid S I have timed these solenoids, so that it reuires about a second for their cores to ully withdraw, and I find that repeated rings of from to *1- of a second are very satisfactory. U on finishing'tlre' conversation the subscriber hangs up, and this is necessary to release the connection. I have contemplated giving control of these connections to the operator, but when the calling subscriber completes the connection himself, and does the ringing, it. is not only logical, but seems to be the best practice to give him controlot the connection thereafter. Upon his hangin up, his line circuit is broken. Current t ien ceases to flow,

the relay S is deenergizcd, the solenoid S loses current and permits its core to sink down, and at the same time the lamp s glows, being lighted by current from the wire 19. The springs ss are separated, and the battery spring 8 is put on the other two, s*-8 which are first joined together before the battery comes on. \Ve then have a circuit from B through 16-17--19, 20s s and s to the wires 13 and 14, 29 and 30, and through the relays V-V simultaneously to ground. Both relays pull up, whereupon the release circuit is closed from ground through 314-54G47 V 48 and battery. The release magnet V thereupon permits the switch to assume its normal position, and the operator perceiving the lamp 5" to glmv, pulls the plug 1, whereupon the relay N releases its armature, and all the parts are again ready for another call, the operator having reset the indicators, as previously stated.

Various modifications can be made in this system, but I contemplate all changes of detail, such as specific arrangement of circuits and the like as being within the scope of my invention, and I desire my claims to be'construed broadly. I believe I am the first to produce what. I may call a double semiautomatic systcin; that is, one in which the completion of the test circuit 43-4A thereindicating calls are distributed first by mnby, a ground on the tip side of the wanted chines controlled by the calling subscribers 5 line will cause the lnstant energiza'fi en of then by operators, and, finally, to wanted subscribers by machines also controlled by the calling subscribers.

Having thus described my invention, what ll claim and desire to secure by Letters Patent is,

1. In atelephone exchange system, a plurality of subscribers lines, a sending device or signal transmitter at each subscribers station, an automatic switch for making connection with a calling subscribers line, another automatic switch for making connect-ion with a wanted subscribers line, and manual connective apparatus between said switches to bring the connecting switches under ,control of the calling subscriber, substantially as described.

2. In a telephone exchange system, the combination of subscribers lines, automatic answering switches and automatic connecting switches, manual. connective apparatus between the switches, and means whereby a subscriber may control the switches, substantialh as described.

In a telephone exchangesystcm, a plurality of subscribers lines, and connective circuits therefor each composed of three parts or lengths, one of which is automatic and controlled by the calling subscriber, the second manually controlled by an operator and the third jointly controlled by both, substantially as described.

4. In a telephone exchange system, the combination with automatic answering and connecting devices adapted to be controlled by a calling subscriber, of manual means for eitecting initial selection of the group con taining the wanted line, substantially as described.

5. in a telephone exchange system, sub scribcrs lines, asignal sending device at each subscribers station, a iirimary selector -h., col'itacts of the lines in switch, ii: line to set of connective autonnitic switches, which are adapted to respond to the action of the subscribers sending de vices, and manual means to connect the primary selector and the contacts of a calling line with the trunk and the connective switches, substantially as described.

6. In a telephone exchange system, subscribers lines, primary selector switches, trunks connected to set of automaticconncctive switches, whereby a calling subscriber may connect himself with any line, subscribers contacts multiplied into the pri' mary selector switches, and manual means for connecting any one of the primary Selectors with any desired trunk, and thereby,

placing the associated switches under con trol of the calling subscriber, substantially as described. r I

'7. ln a telephone exchange system, subscribers lines, primary selector switches, containingv contacts for the lines, automatic connective switches also containing con-- lector switches to connect the same automeans to connect a primary selector with a connective switch, means at the subscribers stations to actuate said connective switches, and means to prevent more than one primary selector from becoming connected to the samevline calling, substantially as-described.

lector switch containing answering terminals for said lines, a setof connective switches and manual means for connecting the same to the primhry selector switches, means associated with a primary selector whereby it may be controlled by a calling subscriber, and further means associated by the calling subscriber to control the connective switches, subs'antially as described.

.9. In av telephone exchange system, a plurality of subscribers lines, a plurality of primary selector switches, each containing multiple terminals of the lines, an automatic connective switch containing calling terminals of subscribers lines, a trunk connection adapted to be manually completed from each primary selector to said connective switch, meansnssociatod with each subscribcrs line to bring an idle primary selector switch into connection with the line when calling, and means associated with each primary selector brought under control of the ailing subscriber by the primary selector to control the connective switch, substantially as described.

10. In an automatic teleplmne exchange system, a plurality of subscribers lines, an automaticselcctor switch containing answering terminals for the lines, means controlled by a subscriber in calling to alter the potential on one or more of his line-termi'-. nals, controlling means for the said switch responding to such altered condition and acting to connect the switch to the line call; ing, an automatic connective switch with manual means whereby it may be connected to the primary selector, and means associated with the primary selector switch and controlled by the calling subscriber for conas described.

11. In an automatic telephone exchange system, a plurality of subscr1bers"lines and swering terminals therefor, a movable mem-- ber for said switch, together with means to drivethe same, so as to connect with any line having terminals therein, a centralized controlling rel'ayassociated with each line,

and a controllingmagnet for the primary selector, an -automat1c connector switch totacts for the lines, means in the primary sea primary selector switch containing .an-'

matically with lines when calling, manual 8. In a telephone exchange system, a plu rality of subscribers lines, a pr1mary se-- with the said primary selector and operable trolling said connective switch, substantially source of current supply for the lines, a

gether with manual means to connect the same to the primary selcctor,-means at the subscribers stations for controlling said connector switch, and multiple connecting terminals for subscribers lines therein, substantially as described.

12. In a telephone exchange system a multi-link central ollicc connective circuit having an automatic switch and its trunk for the answering end, said switch adapted in response to a call over any line to automatically select and connect with said line, another automatic switch and its trunk for the calling end, said'switch containing multiple terminals. of the lines and adapted to be controlled by the calling subscriber so as to pick out and connect with a wanted line, .and means manually controlled for connecting the two ends and thereby performing a part of the selective act in setting up a complete connection, substantially as described.

13. Ina telephone exchange system, subh scribcrs lines each'having means to make and break the metallic circuit, a central current supply, an automatic connective apparatus comprlsing a selecting and calling setof switches and a primary selector switch,

answering line terminals in the latter with a switch member engaging the same and means to drive 1t, a relay associated with each line, a magnet controlled thereby and controlling the primary selector switch when the same engages the line terminals, stopping the switch thereon, controlling magnets for the selective switches, manually connected to the primary selector, and translating relays placed under the line-control by' the primary selector, to control the said switch magnets, substantially as described.

14. In a telephone exchange system, the combination with a group of telephone lines extending from sub-stations to an exchange,

j of aplurality of link connectors at the eX- change, each including a manually-operated terminal at one end ,0f the link circuit, a traveling switch at the other end of each link circuit, means serving to arrest the operation of a .trayeling switch to cause it to 'connect'f'its link-circuit with the telephone line of g, calling subscriber, and a plurality of automatic connective switches'containing multiple terminals of the same lines for seqlecting subscribers wanted, together with 'a trunk connection from each of said 'ra-lity of subscribers lines, a plurality of primary selector switches at a central oflice containing answering terminals for said lines, a plug forming a switching terminal for each prisnary selector, a relay controlled by the subscriber to connect a primary sclector with his line, a relay brought under the control of the subscriber by the primary selector switch for further controlling the said switch, signal devices associated th rewith, a pair of distributing relays controlled by said second relay, and automatic conncc tive switches having trunks terminating in jacks to cooperate with the said plugs, said connective switches bein controlled through the distributing relays Irv the calling subscriber, substantially as described.

16. In a telephone exchange system, a plurality of line circuits, a primary selector responsive to calls over the lines, adapted to connect a calling line to an idle connective circuit, means associated with each line adapted to control a connective circuit when brought into association with its line, and means also associated with each line responsive to the action of the primary switch in effecting connection therewith, to indicate the condition of the line, substantially as described.

17. In a telephone exchange system, a plurality of line circuits and telephone stations thereon, a primary selector switch F0- sponsive to calls over the lines adapted to connect a calling line with an idle connective circuit, means at each station for directively controlling the connective circuit after it is brought into association with the corresponding line, and asignal device at each telephone station to indicate when the line is connected, substantially as described.

18. In a'telephone exchange system, a. plurality of line circuits with telephone stations thereon, a primary selector switch responsive to calls over the lines adapted to connect a calling line with an idle trunk or connective circuit, a. centralized source of currentnormally connected to the lines to furnish current thereto in a definite direction, and connections from said source controlled in the operation of the primary selector switch to reverse the direction of current flow in a line when connected, together with a signal device at each line station,responsive to the reversal of current, to indicate that the line is connected, substantially as described.

In testimony whereof I atiix my signature in presence of two witnesses.

EDWARD E. CLEMENT.

Witnesses:

Hnon M. Sins-mus, J. L. WRIGHT. 

